1. Field of the Invention
This invention relates to an exhaust hood for moving air laden with grease, smoke, vapors, or other contaminants or particulates from a working environment, and more specifically, to such an exhaust hood having an inverted V-shaped transverse configuration for more efficiently funneling the contaminated air from the working environment.
2. Related Art
Exhaust hoods are employed in a variety of environments such as kitchens, laboratories, and commercial food-preparation spaces, in which there are typically several cooking units aligned in a row. Some of these units; e.g., boilers and fryers, may produce considerable quantities of smoke, fumes, grease particles and moisture, while other units, e.g., ranges and griddles, may generate pollutants in substantially smaller amounts. Kitchen exhaust ventilation systems have traditionally been designed with enough airflow capacity to remove pollutants from broilers, fryers, and more active pollution-generating cooking units.
Because of the amount of negative pressure necessary to remove a large volume of contaminants, operating these exhaust ventilators is costly. More particularly, most island-type commercial exhaust hoods having a grease filtering capability include a grease filter installed in the center of the hood cavity at approximately 45.degree. from horizontal in a V-shape having a downwardly directed apex and running the full length of the hood. This configuration is shown as FIG. 1, labeled Prior Art. The principal of operation of this prior art configuration is to create enough negative air pressure in front of the filter in order to capture the heat, smoke, grease and other airborne contaminants and remove them from the working environment.
The negative air pressure downstream of these grease filters must be substantial enough to alter the vertical direction of the hot contaminated air created in the cooking process and draw it toward and then into the grease filters. Failure to exhaust sufficient volumes of air through the filters will result in some hot contaminated air becoming trapped in the hood cavity rather than being exhausted through the filters. Once the hood cavity is filled with the hot, vertically rising, contaminated air that has not been captured by the grease filters, it will begin to escape around the lower edges of the hood into the room or other working space.
The prior-art solution for the foregoing problem, which is commonplace in island-type food preparation surfaces, is to exhaust larger quantities of air through the grease filters until the negative air pressure created is high enough to alter the direction of the vertical air flow toward the grease filter. This requires an exhaust fan; a motor; and a heating, ventilation, and air conditioning ("HVAC") system capable of handling a larger volume of airflow, which, consequently, means higher construction cost when installing the system and higher utility costs when operating the system.
What has been needed is a more efficiently and economically designed hood requiring a smaller or less powerful exhaust fan, motor, and HVAC system, yet providing effective exhaustion of contaminated air.